A unique design concept for miniature axial flow blood pumps is presented that requires no center bearing structure. There is no rotating seal or requirement for a purge fluid. The implanted pump/motor has a volume of 36 cc and weighs approximately 120 gm. Very preliminary tests of several different models of this basic concept in blood show that pump rotors run smoothly without mechanical contact. Flow capacity adequate for a chronic LVAS was also demonstrated. Hemolysis results were higher than what would be acceptable for a chronic pump, although compared to other devices Nimbus has successfully developed, the reduction that must be achieved is not that great. Considering this and the wide design flexibility associated with the concept, achieving acceptable hemolysis levels should be possible. The application's specific aims focus on optimizing the basic design and by bench tests demonstrating a pump that has flow, hemolysis, and endurance performance characteristics adequate for a chronic LVAS blood pump. A miniature pump that combines these virtues with such an elegantly simple design would represent a significant technical innovation. The pump could be incorporated into a small, comparatively inexpensive totally implantable LVAS that would have wide applications to some 17000 to 35000 patients per year who need permanent cardiovascular assistance.